X-ray satellites broadened our horizons

X-ray satellites broadened our horizons

In order to extend observation times, Giacconi initiated the construction of a satellite to survey the sky for X-ray radiation. This satellite was launched in 1970 from a base in Kenya and was given the name UHURU (“freedom” in Swahili). It was ten times more sensitive than the rocket experiments and every week it was in orbit it produced more results than all the previous experiments put together.

However, so far no high-definition X-ray telescope had been sent into space that could provide sharp images. Giacconi constructed one, which was ready for use in 1978. It was called the Einstein X-ray Observatory and was able to provide relatively sharp images of the universe at X-ray wavelengths. Its sensitivity had been improved and objects a million times weaker than Scorpius X-1 (see above) could be recorded.

Fig. 4. A double star that generates X-rays. Gas streams out of the star down towards the compact object and accelerates in its strong gravitational field up to very high speeds. When the gas atoms collide with each other and are decelerated at the surface of the neutron star and by its magnetic field, intensive X-ray                                        radiation is released

This telescope made a large number of discoveries. Many X-ray double stars were studied in detail, not least a number of objects that were thought to contain black holes. More normal stars could also be studied for the first time in X-ray radiation. Remnants of supernovas were analysed, X-ray stars in galaxies outside the Milky Way were discovered and eruptions of X-ray radiation from distant active galaxies could be examined more closely. The X-ray radiation from the gas between galaxies in galaxy groups helped scientists draw conclusions about the dark matter content of the universe.

In 1976 Giacconi initiated the construction of an improved, even larger X-ray observatory. It was not launched until 1999, and was named Chandra after the astrophysicist and Nobel Prize Laureate Subrahmanyan Chandrasekhar. Chandra has provided extraordinarily detailed images of celestial bodies in X-ray radiation corresponding to those from the Hubble Space telescope or the new Earth-based telescopes using visible light.

New light thrown on black holes

Thanks to X-ray astronomy and its pioneers, in particular Giacconi, our picture of the universe has been changed in decisive ways. Fifty years ago our viewpoint was dominated by a picture of stars and star constellations in equilibrium, where any developments were very slow and gradual. Today we know that the universe is also the scene of extremely rapid developments in which enormous amounts of energy are released in processes lasting less than a second, in connection with objects that are not much larger than the Earth, but incredibly compact. Studies of processes at these objects and in the central parts of active galaxy cores are largely based on data from X-ray astronomy. A new, fantastic zoo of important and strange celestial bodies has been discovered and studied. Today the universe seems much more remarkable than we believed 50 years ago – in no small part thanks to X-ray astronomy.

 (http: //www. nobelprize. org/nobel_prizes/physics/laureates/2002/public.

2) Translate the sentences into Russian.

a) The flux of neutrinos from the Sun was estimated to be very large: thousands of billions of solar neutrinos were reckoned to pass through our bodies every second without our noticing them.